1. Technical Field
The invention relates to an apparatus and a method of correcting time difference of a video signal and an audio signal, that is, deviation in Lip-sync.
2. Background Art
Lip-sync is a synchronizing technology of a video signal and an audio signal in reproduction, and various methods have been proposed so far to realize Lip-sync. FIG. 24 shows an example of a conventional video-audio synchronizing system. In a source device 210, a same time stamp (time code) is multiplexed on video signal and audio signal. The video signal and audio signal on which the time stamp is multiplexed pass through various paths such as the repeaters 214 and 216, and both are finally supplied to a sink device 220. In the sink device 220, the time stamp of video signal and the time stamp of audio signal are retrieved, and the difference is detected by a time code comparator 222. On the basis of the detected difference, a video delay device 224 and an audio delay device 226 located at the final points of the respective paths are controlled. For example, when the video signal is later than the audio signal, an extra delay is given to the audio signal, and the total delay time of both signals is controlled to be identical.
Patent document 1 discloses a technology for automatically correcting the time deviation of audio signal, by comparing the time stamps of video signal and the audio signal, and delaying either the video signal or audio signal, so that the both may be matched.    Patent document 1: JP-A-2003-259314